For centuries, posts have been driven into the ground by applying an essentially downward force at or near the top of a post. Humans may apply intermittent, brute force with sledgehammers or similar instruments. Machines may apply such force continuously or intermittently so long as the total energy imparted is sufficient to embed the post to a desired depth while not damaging the post. Pistons, actuated mechanically or hydraulically, may lack portability, be unwieldy, or cause post damage.